Question

Which of these phenomena results in viscous dissipation?

(a) Kinetic energy transformed into internal energy

(b) Acceleration of flow

(c) Temperature gradient

(d) Hot wall and cold wall case

I got this question in an interview.

This question is from Couette Flow in chapter Numerical Techniques for Nonlinear Supersonic Flow, Elements of Hypersonic Flow, Couette and Poiseuille Flow of Aerodynamics

Answer 1

The correct choice is (a) Kinetic energy transformed into internal energy

Easy explanation: The flow has kinetic energy which is partially dissipated in the form of internal energy due to the presence of skin friction drag that exists between the fluid and the flat plate. The change in internal energy leads to change in dissipation. These particular phenomena are known as viscous dissipation.